39813661 has 2 divisors, whose sum is σ = 39813662. Its totient is φ = 39813660.

The previous prime is 39813659. The next prime is 39813749. The reversal of 39813661 is 16631893.

39813661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23765625 + 16048036 = 4875^2 + 4006^2 .

It is a cyclic number.

It is not a de Polignac number, because 39813661 - 2¹ = 39813659 is a prime.

Together with 39813659, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 39813661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39813601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19906830 + 19906831.

It is an arithmetic number, because the mean of its divisors is an integer number (19906831).

Almost surely, 2^39813661 is an apocalyptic number.

It is an amenable number.

39813661 is a deficient number, since it is larger than the sum of its proper divisors (1).

39813661 is an equidigital number, since it uses as much as digits as its factorization.

39813661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 37.

The square root of 39813661 is about 6309.8067323810. The cubic root of 39813661 is about 341.4633038734.

The spelling of 39813661 in words is "thirty-nine million, eight hundred thirteen thousand, six hundred sixty-one".